Experiments are designed to study mechanisms responsible for functional increase in the Ia-motoneuron projection. We are anxious to further examine the time course of this phenomenon to see whether separate acute and chronic mechanisms exist. We will attempt to extend the generality of these findings using other projections. We will also be examining the fluctuations in synaptic delays of EPSPs to see whether these change after transection which would indicate a presyanptic locus for change after transection. We will continue our anatomical studies of the spinal projection of afferent fibers supplying transplanted supernumerary limbs in Xenopus.